Data Integration Data integration o Combines data from multiple sources into a coherent store ■ Schema integration:e.g.,A. cust-id≡B.cust# o Integrate metadata from different sources Entity identification problem Identify real world entities from multiple data sources, e. g, Bill Clinton= William clinton a Detecting and resolving data value conflicts For the same real world entity, attribute values from different sources are different Possible reasons: different representations, different scales, e. g metric vs. British units 同济大学软件学院 13 ool of Software Engineering. Tongpi Unversity13 13 Data Integration ◼ Data integration: ◆ Combines data from multiple sources into a coherent store ◼ Schema integration: e.g., A.cust-id  B.cust-# ◆ Integrate metadata from different sources ◼ Entity identification problem: ◆ Identify real world entities from multiple data sources, e.g., Bill Clinton = William Clinton ◼ Detecting and resolving data value conflicts ◆ For the same real world entity, attribute values from different sources are different ◆ Possible reasons: different representations, different scales, e.g., metric vs. British units